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Numerical Simulations of Droplet Aerobreakup

Citation

Meng, Jomela Chen Chen (2016) Numerical Simulations of Droplet Aerobreakup. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z9KW5D09. http://resolver.caltech.edu/CaltechTHESIS:05262016-092840941

Abstract

The work presented in this thesis aims to bridge an existing gap in the state of droplet aerobreakup knowledge associated with the fundamental flow physics that govern the experimentally observable droplet morphologies. Using direct numerical simulations of the aerobreakup of water cylinders and droplets in the flow behind shock waves in air, we investigate the behavior of the surrounding gas flow to gain insight into the droplet’s deformation and evolution in the stripping breakup regime. The compressible multicomponent Navier-Stokes equations are solved using the Multicomponent Flow Code — a high-order accurate structured finite-volume flow solver with shock- and interface-capturing. Following qualitative descriptions of the aerobreakup process, comparisons are made with available experimental data. In 2D, accurate measurements of the cylinder’s center-of-mass acceleration across a range of incident shock Mach numbers allow characterization of the unsteady drag coefficient. Additionally, mass loss measurements from viscous simulations refute a well-known boundary layer stripping theory. The results of a 3D nonaxisymmetric aerobreakup simulation are presented with an emphasis on describing the intricate flow phenomena observable in the wake region. Subsequent analyses of the surface instabilities and a Fourier decomposition of the flow field reveal asymmetrical azimuthal modulations and broadband instability growth that result in the devolution of the wake region into chaotic flow.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:droplet; aerobreakup; compressible flows; multicomponent; multiphase flows; instabilities; breakup; secondary atomization
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Awards:Richard Bruce Chapman Memorial Award, 2016
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Colonius, Timothy E.
Thesis Committee:
  • Shepherd, Joseph E. (chair)
  • Colonius, Timothy E.
  • Blanquart, Guillaume
  • Austin, Joanna M.
Defense Date:3 May 2016
Funders:
Funding AgencyGrant Number
NIH2P01-DK043881
Energent CorporationUNSPECIFIED
Record Number:CaltechTHESIS:05262016-092840941
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:05262016-092840941
DOI:10.7907/Z9KW5D09
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1007/s00193-014-0546-zRelated DocumentArticle: Numerical simulations of the early stages of high-speed droplet breakup
http://resolver.caltech.edu/CaltechAUTHORS:20160526-114025207Related DocumentConf. paper: Droplet Breakup in High-Speed Gas Flows
http://dx.doi.org/10.1007/978-3-319-16838-8_120Related DocumentConf. paper: The Effects of Shock Strength on Droplet Breakup
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9764
Collection:CaltechTHESIS
Deposited By: Chen Chen Meng
Deposited On:26 May 2016 20:42
Last Modified:26 May 2016 20:42

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